The proposed secondary analysis of data from the National Institute of Child Health and Human Development (NICHD) Study of Early Child Care and Youth Development (SECCYD) will focus on assessing the role of chronic illness, such as asthma, on the emotional, developmental, and behavioral health of children. Sophisticated data analysis techniques will be used to model the development of chronic illnesses over time, while at the same time trends of developmental health will be modeled from the longitudinal data. Taking into account the confounding effect of various demographic, socioeconomic, and child care factors, the impact of chronic illness on the observed trends of emotional, developmental, and behavioral health over time will then be assessed. The complications involved with simultaneous modeling of both chronic illness as well as developmental health measures over time will require further advances of statistical methodologies to best address this proposed aim of the study.